BER testing measures which of the following?

• A. Ratio of transmitted bits to received bits.
• B. Ratio of incorrectly received bits to total transmitted bits.
• C. Ratio of power in signal to power in noise.
• D. Ratio of symbol rate to bit rate.

Answer: (C)

BER testing looks at how often bits are received in error. It is the fraction of transmitted bits that arrive incorrectly, computed as the number of bit errors divided by the total number of bits sent. This metric directly quantifies the quality of the link for digital data and is influenced by factors like noise, interference, and modulation scheme—the higher the signal quality, the lower the BER tends to be.

So, the correct idea is the ratio of incorrectly received bits to the total transmitted bits. The ratio of transmitted bits to received bits and the ratio of symbol rate to bit rate do not measure errors per se, and the ratio of signal power to noise power is the signal-to-noise ratio, which relates to BER but is not BER itself.